Case Example 5 (Multiple Primaries and Histology)

10/25, outside community hospital: bone marrow biopsy: Hypercellular marrow (70%) W/ trilineage hyperplasia & adequate maturation. Mild dyserythropoiesis W/ 3% ring sideroblasts & micromegakaryocytes identified. INCR marrow storage iron. Moderately INCR reticulin fibrosis W/ focal collagen fibrosis (WHO MF-2 W/ focal MF-3). Findings raise consideration of an overlap myeloproliferative neoplasm / myelodysplastic syndrome (MPN/MDS). JAK2 (-).

12/25 bone marrow biopsy: Myeloid neoplasm post cytotoxic therapy. 5q31 (EGR1): Deletion detected. 7q31 (D7S486): Deletion detected. 17p13.1 (p53): Deletion of gene detected.

Involvement Comments
Lymph nodes N/A
Organ involvement N/A
Common metastatic sites N/A

Coding of the case (Heme Retic Schema)

Data Item-Primary #1 Coding
M Rule M15. Use the multiple primaries calculator. These are two separate myeloid neoplasms.
PH Rule PH30: Use the Heme DB
Primary site C421 (Bone marrow)
Per the Heme DB, primary site must be C421
Histology Primary #1: 9975/3: MDS/MPN, NOS
Pathology report does state “findings raise consideration of an overlap MDS/MPN,” which is ambiguous terminology; however, there is enough information to code this as myeloid neoplasm. Myeloid neoplasm is an alternate name for MPN/MDS, NOS
Diagnostic confirmation 1 (positive histology)
EOD Primary Tumor 800 (MDS/MPN always 800)
EOD Regional Nodes 888 (not applicable)
EOD Mets 88 (not applicable)
Summary Stage 7 (MDS/MPN always distant)
Mets at Dx Data Items (all 6) 8 (not applicable for all)
Data Item-Primary #2 Coding
M Rule M15. Use the multiple primaries calculator. These are two separate myeloid neoplasms.
PH Rule PH30: Use the Heme DB
Primary site C421 (Bone marrow)
Per the Heme DB, primary site must be C421
Histology Primary #2: 9920/3: Therapy related neoplasm
Note: Myeloid neoplasm post cytotoxic therapy is an alternate name under 9920/3
Diagnostic confirmation 1 (positive histology)
EOD Primary Tumor 800 (leukemias always 800)
EOD Regional Nodes 888 (not applicable)
EOD Mets 88 (not applicable)
Summary Stage 7 (leukemias always distant)
Mets at Dx Data Items (all 6) 8 (not applicable for all)

Updated: December 2, 2025